1612 THE VOYAGE OF H.M.S. CHALLENGER. 



Subfamily 2. SAGMARIDA, Haeckel. 



Definition, S agosphserida with a spongy spherical shell, the thickened wall 

 of which is composed of a loose spongy framework. 



i 



Genus 679. Sagmarium, n. gen. 



Definition. S agosphserida with a spongy spherical shell, the thickened wall 

 of which is composed of a loose spongy framework, and exhibits a smooth surface, 

 without radial spines, and pyramidal elevations. 



The genus Sagmarium, and the following two genera of Sagosphserida, represent 

 together the subfamily Sagmarida, differing from the preceding Sagenida in the spongy 

 structure of the shell-wall. Whilst in the latter the thin wall of the delicate spherical 

 shell is composed of a simple lattice-plate with triangular meshes, in the former numerous 

 branches diverge from the nodal points of these meshes, and produce by union an 

 irregular and loose spongy framework. The surface of this spongy hollow sphere 

 (similar to Plegmosphssra) is in Sagmarium smooth. 



1. Sagmarium spongodictyum, n. sp. (PI. 108, fig. 2). 



Spongy wall of the hollow sphere about half as thick as the radius of its cavity. Bars of the 

 spongy framework very thin and fragile, smooth, without thorns. 



Dimensions. Diameter of the sphere 2'0 to 2'4 ; length of the bars O'l to 0'2, breadth O'OOl. 

 Atlantic, Station 333, surface. 



2. Sagmarium plegmosphcerium, n. sp. (PI. 108, fig. 14). 



Spongy wall of the hollow sphere about one-fourth as thick as the radius of its cavity. Bars 

 of the spongy framework rather stout, studded with numerous small spines, which arise perpen-' 

 dicularly from their surface. 



Dimensions. Diameter of the sphere 1'2 to 1'5, length of the bars O'l to 016, breadth 0'004. 



Habitat. Tropical Atlantic, Station 347, surface. 



3. Sagmarium trigonizon, Haeckel. 



Didyosoma triyonizon, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 841. 

 Spongodictyon trigonizon, Haeckel, 1862, Monogr. d. Eadiol., p. 459, Taf. xxvi. figs. 4, 5. 



Bars of the spongy framework thin, irregularly curved, bearing scattered small crosses, which 

 are composed of four small rods arising perpendicularly from the bars. Nod.al points of the frame- 



1 Sagmarium = Covering of a shield, armour ; <rxyftii%io!>. 



